Chest - regional anatomy

bones of the thorax

• sternum

• costal cartilages

• 24 ribs

• 12 thoracic vertebrae

diagram of bones of thorax

features of thoracic cage

• sternum - long flat bone, composed of manubrium, body and xiphoid process

• true ribs - ribs 1-7: articulates with sternum directly

• false ribs - ribs 8-12: articulates to costal cartilages of the ribs above

• floating ribs - ribs 11 and 12: articulate with vertebrae only

boundaries of thorax - thoracic inlet

boundary between neck and thorax. Bounded posteriorly by T1, anteriorly by manubrium, and laterally on each side by 1st rib

boundaries of thorax - anterior and lateral walls, and floor

Anterior wall - formed by sternum, costal cartilages and anterior ends of the ribs and intercostal muscles

lateral wall - formed by ribs and intercostal muscles

floor - formed by diaphragm

contents of thorax - pleural cavities

• right and left pleural cavities

• pleura - visceral, parietal

• right lung - 3 lobes

• left lung - 2 lobes

• each lung has; apex, base, costal surface and medial surface with a hilum

contents of thorax - mediastinum

The potential space between lungs, consists of organs/structures of following systems;

• cardiovascular

• respiratory

• digestive

• lymphatic

superior mediastinum

Lies above an arbitrary line drawn between the manubriosternal junction and the lower border of T4. Contents;

• aortic arch and main branches

• brachiocephalic artery and veins

• part of superior vena cava

• trachea

• oesophagus

• upper part of thoracic duct

• thymus gland

• vagus nerve

• phrenic nerve

diagram of contents of superior mediastinum

Antero mediastinum

Lies in front of heart and pericardium. Contents;

• loose fatty tissue

• lymph nodes

• internal mammary arteries

Middle mediastinum

Lies behind antero mediastinum. Contents;

• heart and pericardium

• ascending aorta

• superior vena cava

• pulmonary a

Posterior mediastinum

Lies behind middle mediastinum. Contents;

• descending thoracic aorta

• oesophagus

• azygos veins

• lymph nodes

Anatomical landmarks of Thorax

• sternal notch - depression on upper border of manubrium. At level T2/3

• sternal angle - Junction of manubrium and body of sternum. Level T4

• Xiphoid process - small cartilaginous part of sternum which gradually ossifies during adult lift

• xiphisternal joint - junction xiphoid process and body of sternum. T9

• Inferior angle of scapula - lower, pointed part of scapula

• lower costal margin - lower edge of thorax formed by inferior edge of ribcage. L3

Reasons for referral

• lung cancer diagnosis

• trauma

• ? pneumothorax

• pericardial effusion

• heart/valve disease

• pneumonia

• pleural effusion

• shortness of breath

• weight loss

• chest pain

RCR reasons for referral (royal college of radiologists)

• acute onset or chronic chest disease

• acute chest pain

• trauma

• occupational health screening

• pre operative assessment

• post thoracic surgery

• ventilated patients

Clinical conditions RCR 1998

• Myocardial infarction (MI) - assessment of heart size

• chest pain - exclude other causes, rarely diagnostic

• acute aortic dissection - CT more helpful

• chest trauma - query pneumothorax

• pneumonia follow up - confirm resolution (>10 days)

• Haemoptysis - +lateral

• Intensive Therapy Unit (ITU) - symptomatic change

• pulmonary embolus - CT or Nuclear medicine more definitive

• pericarditis

• pericardial effusion - US more helpful

• chest trauma - if ? pneumothorax

NICE (2015) guidance changes

no longer require persistent signs or symptoms (lasting more than 3 weeks)

guidance now relates to patients over 40

Urgent CXR referral (USC)

people aged 40 and over, if they have 2 or more of these unexplained symptoms, or smokers/ex smokers if they have 1 or more;

• cough

• fatigue

• shortness of breath

• chest pain

• weight loss

• appetite loss

NICE (2015) urgent request for any of the following

• persistent or recurrent chest infection

• finger clubbing

• supraclavicular lymphadenopathy or persistent cervical lymphadenopathy

• chest signs consistent with lung cancer

• thrombocytosis

contraindications (where something isn’t medically advised)

• non specific chest pain - main purpose is reassurance

• suspected rib # - doesn’t change management

• pre employment screening - only justified in high risk (eg. divers)

• upper respiratory tract infection - follow up after treatment only valuable after 10+ days

• chronic obstructive lung disease - only if symptoms change

PA Chest

• patient erect facing bucky

• centre midsaggital plane of patient to midline of IR

• relax and roll forward shoulders

• upper border of IR is 5cm above shoulder

• raise chin and place back of hands against lower hips and roll shoulders forward (or hug bucky if unstable or elderly) (this clears scapulae off lung fields)

Area covered in PA chest

• lung fields

• apices

• costophrenic angle

• heart

PA chest collimation

Include 5ch above shoulder to include upper airway. Ensure lung bases included.

Include acromioclavicular joints (AC joints) laterally.

Anatomy visualised on chest radiograph

• heart

• lung parenchyma

• pleura

• chest wall

• diaphragm

• mediastinum

• hilum

chest - 10 point checklist

1. correct examination undertaken

2. patient ID

3. hospital identification

4. correct anatomical marker positioned in primary beam

5. correct area included on image

6. adequate breath in

7. adequate exposure

8. artefacts

9. pathology

10. inspiration

cardiothoracic ratio

ratio of max horizontal cardiac diameter to max horizontal thoracic diameter. Normal <50%